Recalibration of a tunable lamp system

ABSTRACT

Some embodiments include a method of operating a tunable light module. The method can include driving a lamp in the tunable light module, having lamps of at least two colors, to produce a colored light according to the color mixing plan that corresponds to a correlated color temperature (CCT); measuring a light characteristic of the lamp using a light sensor; detecting a degradation level by comparing the measured light characteristic against an expected light characteristic; and adjusting a current level for driving the lamp at the CCT by referencing the color mixing plan and an alternative coefficient corresponding to the degradation level.

CROSS-REFERENCE TO RELATED APPLICATION(S)

This application claims the benefit of U.S. Provisional PatentApplication No. 62/153,953, entitled “RECALIBRATION OF A TUNABLE LAMPSYSTEM,” which was filed on Apr. 28, 2015, which is incorporated byreference herein in its entirety.

RELATED FIELD

At least one embodiment of this disclosure relates generally to atunable lighting system, and in particular to controlling tunableLED-based lamp modules.

BACKGROUND

Conventional systems for controlling lighting in homes and otherbuildings suffer from many drawbacks. One such drawback is that thesesystems rely on conventional light sources, such as incandescent bulbsand fluorescent bulbs. Such light sources are limited in many aspects.For example, such light sources typically do not offer long life or highenergy efficiency. Further, such light sources offer only a limitedselection of colors, and the color or light output of such light sourcestypically changes or degrades over time as the bulb ages. In systemsthat do not rely on conventional lighting technologies, such as systemsthat rely on light emitting diodes (“LEDs”), long system lives arepossible and high energy efficiency can be achieved. However, in suchsystems issues with color quality can still exist.

A light source can be characterized by its color temperature and by itscolor rendering index (“CRI”). The color temperature of a light sourceis the temperature at which the color of light emitted from a heatedblack-body radiator is matched by the color of the light source. Thecolor temperature is useful to emulate different states of natural lightproduced from the sun. For a light source that does not substantiallyemulate a black body radiator, such as a fluorescent bulb or an LED, thecorrelated color temperature (“CCT”) of the light source is thetemperature at which the color of light emitted from a heated black-bodyradiator is approximated by the color of the light source. The CRI of alight source is a measure of the ability of a light source to reproducethe colors of various objects faithfully in comparison with an ideal ornatural light source. The CCT and CRI of LED light sources are typicallydifficult to tune and adjust. Further difficulty arises when trying tomaintain an acceptable CRI while varying the CCT of an LED light source.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1A is a graph illustrating an example of maximum brightness levelsat different color temperatures for a tunable light module when thetunable light module prior to deployment, in accordance with variousembodiments.

FIG. 1B is a graph illustrating an example of maximum brightness levelsat different color temperatures for the tunable light module of FIG. 1Aafter the tunable light module experiences degradation, in accordancewith various embodiments.

FIG. 1C is a graph illustrating an example of maximum brightness levelsat different color temperatures for the tunable light module of FIG. 1Cafter the tunable light module is recalibrated after degradation, inaccordance with various embodiments.

FIG. 2A is a block diagram of a model builder system for generating acolor mixing plan at a pre-deployment stage of a tunable light module,in accordance with various embodiments.

FIG. 2B is a flow chart illustrating a method of generating a colormixing plan at a pre-deployment stage of a tunable light module, inaccordance with various embodiments.

FIG. 2C is a graph illustrating an example of a color mixing planincluding an optimized CRI.

FIG. 2D is a graph illustrating corresponding luminous efficacy of colorpoints in the color mixing plan of FIG. 2B.

FIG. 3 is a block diagram of a LED-based tunable light module, inaccordance with various embodiments.

FIG. 4 is an illustration of a configurable lamp system to operate atunable light module, in accordance with various embodiments.

FIG. 5 is a flow chart of a method of pre-computing adjustments to acolor mixing plan of a tunable light module at the pre-deployment stageto support recalibration after deployment, in accordance with variousembodiments.

FIG. 6 is a flow chart of a method of recalibrating a color mixing planof a tunable light module after deployment, in accordance with variousembodiments.

FIG. 7 is a flow chart of a method of real-time re-optimization of acolor mixing plan of a tunable light module after deployment, inaccordance with various embodiments.

FIG. 8 is a diagrammatic representation of a machine in the example formof a computer system within which a set of instructions, for causing themachine to perform any one or more of the methodologies or modulesdiscussed herein, may be executed.

The figures depict various embodiments of this disclosure for purposesof illustration only. One skilled in the art will readily recognize fromthe following discussion that alternative embodiments of the structuresand methods illustrated herein may be employed without departing fromthe principles of the invention described herein.

DETAILED DESCRIPTION

Disclosed is a system architecture of configuring a lamp system toaccurately and consistently produce light in accordance with a usersetting. The lamp system can include one or more tunable light modules,such as LED-based lamp modules. The tunable light modules can beindependently replaceable.

A tunable light module includes two or more lamps (e.g., LEDs) of atleast two colors. Each of the lamps can produce illumination havingdifferent spectral distribution (e.g., peaks and valleys at differentfrequencies). A mixing chamber and/or a light pipe of the tunable lightmodule can mix the light produced from the lamps and emit the mixedillumination (i.e., output illumination) through an exit aperture. Acontroller of the tunable light module can change characteristics (e.g.,color temperature, saturation, hue, brightness, etc.) of the mixedillumination produced from the lamps by referencing a color mixing plan.

A color mixing plan can be a set of associations that specifies how toachieve different characteristics of the output illumination under agiven operational condition and given constraints of performancemetrics. The set of associations can be stored in any suitable form,such as a reference table (more memory intensive) or a polynomialfunction (more processor intensive). For example, a color mixing plancan specify driving conditions (e.g., current levels and/or signalpatterns, such as different pulse width modulations) for each of thelamps to achieve a color characteristic (e.g., CCT) at a particularoperational temperature. In some embodiments, the color mixing planspecifies luminous flux required from each of the lamps to achieve acolor characteristic at an operational temperature. The operationalcondition may include a junction temperature, a mixing chambertemperature, a heat sink temperature, or a combination thereof. Theconstraints can include an efficacy constraint, an efficiencyconstraint, a maximum brightness constraint (e.g., per color channel oroverall), CRI constraints, or any combination thereof.

The color mixing plan may be generated at a pre-deployment stage of thetunable light module. The pre-deployment stage may refer to themanufacturing stage, the assembly stage, or any time before a merchantships the tunable light module to customers. For example, the colormixing plan can be generated based on a lamps color space map of thetunable light module. A model builder system can generate the lampscolor space map during a pre-deployment stage for a tunable lightmodule. Because of minor differences in material and manufacturingprocess, not all lamps/LEDs of the same color type produce the samelight characteristic under the same driving and/or operationalconditions. Furthermore, because of minor geometric configurationdifferences between LED sets and the variations amongst LEDs of the samecolor type, tunable light modules might not produce the same lightcharacteristics under the same operating conditions. The lamps colorspace map can capture the unique characteristic of the LEDs in eachtunable light module.

The model builder system includes a spectral analyzer. The lamps colorspace map may include spectral analysis of each lamp or each colorchannel under different operational conditions and different drivingconditions (e.g., driving current and/or driving signal pattern). Thelamps color space map may be generated by driving each lamp or colorchannel through a range of possible driving conditions and monitoringthe spectral characteristics and the operational conditions associatedwith each driving condition. In some embodiments, the model buildersystem can also iterate through different operational conditions, suchas generating different temperature scenarios externally. The modelbuilder system can save the mapping of the driving conditionscorresponding to the operational conditions and the spectralcharacteristics into the lamps color space map. For example, the lampscolor space map can be generated based on the method described in FIG.2B and stored in a memory device accessible later on after deployment.

The model builder system can index the spectral characteristics of eachoperational condition and each driving condition for a color channel ina variety of ways. For example, the model builder system can drive onecolor channel at a time and monitor its spectral characteristics. Foranother example, the model builder system can drive a first set of colorchannels including the intended color channel and drive a second set ofcolor channels, that is the first set minus the intended color channel.The difference between the spectral characteristics of the first set andthe second set can be stored as the spectral characteristics of theintended color channel.

In some embodiments, the model builder system can also monitor thejunction temperature of the lamps (e.g., LEDs) as the model buildersystem iterates through the range of driving conditions to build atransient temperature map. For example, the model builder system can usethe spectral analyzer to estimate the transient junction temperature oruse a thermal sensor. Using the temperature map and a model of thethermal capacitance and resistance of materials and structures insidethe tunable light module, the model builder system can generate athermal model that enables the tunable light module to accuratelypredict its junction temperature or operational temperature. In someembodiments, the thermal model can incorporate both a thermalcapacitance and resistance model and a transient temperature model.

The tunable light module may include a temperature sensor. Thetemperature sensor may not be immediately adjacent to the lamps.However, the thermal model can be used to accurately estimate thejunction temperature at the lamps. For example, the temperature measuredat the temperature sensor can provide an estimate of the ambienttemperature within the tunable light module. The thermal model can beused to estimate the effect of the ambient temperature at the lamps. Forexample, the thermal capacitance and resistance of the structures can beused to estimate the effect of that ambient temperature. The transienttemperature model can further enable the tunable light module to predictthe transient temperature in response to the driving conditions. Acombination of the estimated transient temperature and the measuredambient temperature can accurately predict the actual junctiontemperature.

Given a desired spectral characteristic, there may be differentpermutations of operational conditions that can achieve the samespectral characteristic. For example, there may be multiple differentways to drive three color LEDs to achieve a color temperature of 2200K.The different ways of driving the three color LEDs may differ inperformance metrics (e.g., maximum brightness, efficacy, efficiency,and/or CRI). The computing device can use a multivariate solver tooptimize the performance metrics to select driving conditions thatmatches manufacturer specified constraints. For example, themultivariate solver can take the lamps color space map and performancemetric constraints as inputs, and produce the optimized color mixingplan as an output.

The optimized color mixing plan is stored in a memory of the tunablelight module. In some embodiments, the thermal model is also stored inthe memory. In some embodiments, the lamps color space map is also bestored in the memory. In some embodiments, the model builder system canassociate the lamps color space map with an identifier of the tunablelight module and save the lamps color space map and its associations ina cloud storage system.

The color mixing plan enables the controller of the tunable light moduleto produce user-specified spectral characteristics on the fly underoptimal conditions according to the manufacturer specified constraints.However, the color produced by the tunable light module may shift overtime (e.g. a tristimulus shift). This is caused by various reasons,including browning of a LED cap, phosphorus popping of aphosphorus-based LED, the degradation of silicone in an LED or anyoptical coupling in the tunable light module, other chemical, materialor mechanical related degradation, or any combination thereof.

A mobile device can couple to one or more tunable light modules toestablish a lamp group. The mobile device can be a general purposedevice having an operating system implemented thereon (e.g., by aprocessor executing executable instructions stored in a memorycomponent). The operating system can enable the mobile device todownload, install, implement a light control application thereon.

The light control application provides a user interface (e.g., atouchscreen interface) for a user to configure a tunable light module orthe lamp group as a whole. The light control application can control thetunable light modules via wireless protocols (e.g., Bluetooth or WiFi).For example, the tunable light modules can include an integratedcommunication module therein, or be coupled to an adapter box thatreceives and interprets the communication from the light controlapplication. The tunable light module has the capability of colormatching color spectrums or characteristics (e.g., color temperatures,brightness, and hue) based on the color mixing plan. The light controlapplication can send or schedule commands actively (e.g., based on auser command) or passively (e.g., automatically as a background processwithout a user command) to activate the color matching process on thetunable light module. The light control application can further receivestatus information regarding the tunable light module including faultdetection, estimated life time, temperature, power consumption, or anycombination thereof.

In some embodiments, the light control application can initiate (e.g.,automatically or based on a user command) a lamp maintenance process,including re-calibration and data collection. For example, the lightcontrol application can communicate (e.g., via WiFi or cellular dataplan) with a computer server (e.g., the cloud storage server) thatstores light configuration data (e.g., CCT, brightness, saturation,and/or hue) and operating state data (e.g., temperature, current, actualCCT level, or other light characteristic data from sensors of a lampmodule) for each of the lamp group or lamp modules. The computer servercan re-compute and/or re-optimize a color mixing plan for a lamp modulebased on the recorded history of operating state data and lightconfiguration data. The computer server can then push the updated colormixing plan back to the lamp module through the mobile device runningthe light control application. In some embodiments, the computer server,the light control application, the lamp module, or a combinationthereof, can maintain the recorded history of configuration data andoperating state data of the lamp module.

In some embodiments, instead of controlling the tunable light moduleswith a general-purpose mobile device, a controller device coupled to thetunable light modules via a wired interconnect can also control thetunable light modules. For example, the controller device cancommunicate directly through the wired interconnect with an integratedcommunication module in a tunable light module or indirectly through anadapter box outside of the tunable light module that interprets and/orconverts the control signal from the controller device.

Disclosed are different methods of recalibrating the color mixing planafter decalibration due to certain types of degradation. Recalibrationcan enable the tunable light modules to more accurately produceillumination characteristics as intended (e.g., as commanded by acontroller/mobile device). Recalibration of the color mixing plan canalso enable the tunable light module to meet existing constraints ofperformance metrics. For example, the recalibration can enable thetunable light module to meet the same maximum brightness level asbefore. Conventionally, tunable light modules are set with more lenientconstraints (e.g., the tunable light module being capped at a lowerbrightness level) such that users would not notice a degradation to theperformance metric after decalibration. The disclosed methods overcomethe necessity of this type of performance capping before deployment.

In some embodiments, during the pre-deployment stage, the model buildersystem can compute different alternative coefficients (e.g., for alookup table or a polynomial function) stored in the color mixing planto adjust the color mixing plan when degradation is detected. Thesealternative coefficients are calculated based on a set of constraintsgiven at the pre-deployment stage. For example, a tunable light modulecan include a light sensor (e.g., a PIN diode or a tristimulus sensor).After deployment, the tunable light module can use the light sensor todetermine how much degradation occurred in each color channel. Thetunable light module can then select an alternative coefficientassociated with a color channel based on the degradation level of thatcolor channel to recalibrate.

In some embodiments, the model builder system can compute thealternative coefficients based on the degradation type. For example, afirst set of alternative coefficients can correspond to plastic browningand a second set of alternative coefficients can correspond tophosphorus popping. For various types of degradation, the tri-stimulusshift function is relatively stable over time. Accordingly, the modelbuilder system can provide alternative coefficients that correspond todifferent levels of degradation. The light sensor in the tunable lightmodule can then, in real-time after deployment, determined thedegradation level and select the alternative coefficients to use.

In some embodiments, when calibrating after deployment, the tunablelight module can monitor brightness levels under pre-determined drivingconditions for each color channel. For example, the light module canswitch through each color channel under the predetermined drivingconditions. The tunable light module can send the brightness levelsassociated with the predetermined driving conditions to a mobile device.In turn, the mobile device can send the brightness levels associatedwith the predetermined driving conditions to a cloud server. The cloudserver can access the lamps color space map associated with the tunablelight module and re-compute the color mixing plan by normalizing oraligning the lamps color space map to the amount of degradation observedin each color channel. The cloud server can re-compute the color mixingplan based on the constraints on the performance metrics set at thepre-deployment stage. The cloud server can also re-compute the colormixing plan based on a new set of constraints on the performance metric.For example, the new set can be specified by the user of the mobiledevice coupled to the tunable light module. For another example, the newset can be updated by the merchant controlling the cloud server.

In some embodiments, the tunable light module can include a spectralanalyzer. In those embodiments, the tunable light module can update thelamps color space map at the deployment stage. For example, the tunablelight module can run a background process to spectrally analyze theillumination produced during different driving conditions andoperational conditions. The spectral analysis can be updated to thecloud server through the mobile device. The cloud server can then updatethe lamps color space map based on the new spectral analysisinformation. In some embodiments, the lamps color space map can bestored on the tunable light module. In those embodiments, the lampscolor space map can be updated in real-time on the tunable light moduleand the color mixing plan can be re-computed using a processor of thetunable light module.

FIG. 1A is a graph 102 illustrating an example of maximum brightnesslevels at different color temperatures for a tunable light module whenthe tunable light module prior to deployment, in accordance with variousembodiments. The tunable light module can emulate a black body radiatorat different color temperatures. The graph 102 illustrates the maximumbrightness levels at a range of color temperatures when the tunablelight module is driving its color lamps (e.g. LEDs) according to a colormixing plan.

FIG. 1B is a graph 104 illustrating an example of maximum brightnesslevels at different color temperatures for the tunable light module ofFIG. 1A after the tunable light module experiences degradation, inaccordance with various embodiments. As described above, over time, thecolor lamps inside the tunable light module can degrade. For example,this can be due to plastic browning, silicone degradation, opticalcoupling degradation, phosphorus popping in phosphorus-based LEDs, orany combination thereof. After at least some of the color channelsdegrade, the maximum brightness levels at the color temperatures maydecrease as illustrated. Furthermore, other performance metrics (e.g.,CRI, efficiency, or efficacy) may have fallen with the degradation aswell.

FIG. 1C is a graph 106 illustrating an example of maximum brightnesslevels at different color temperatures for the tunable light module ofFIG. 1B after the tunable light module is recalibrated afterdegradation, in accordance with various embodiments. The graph 106illustrates the benefit of recalibration. After recalibration, thetunable light module can generate illumination at the same range ofcolor temperatures as at the pre-deployment stage. Furthermore, thetunable light module can improve at least one of the performance metricsby modifying/adjusting the color mixing plan. In the illustrated case,the tunable light module is able to improve the maximum brightness atseveral color temperatures as compared to the levels after degradationand prior to recalibration as shown in FIG. 1B.

FIG. 2A is a block diagram of a model builder system 200 for generatinga color mixing plan 202 at a pre-deployment stage of a tunable lightmodule 204, in accordance with various embodiments. The tunable lightmodule 204 or the LEDs of the tunable light module 204 can be placedinside a test chamber 206, free from any thermal, electrical, and/oroptical pollution and interference. The test chamber 206 can behermetically sealed.

The model builder system 200 can include a computer system 208. Thecomputer system 208 contains logic for the building of the color mixingplan 202. The computer system can be coupled to a power supply 210 forthe tunable light module 204. The power supply 210 can be the powersupply that will be used by the tunable light module 204 afterdeployment or an external power supply. The computer system 208 caniterate through different driving conditions for one or more LEDs forthe tunable light module 204 using the power supply 210. In someembodiments, while testing, the one or more LEDs are yet to be installedin the tunable light module 204. In response to the driving currentsfrom the power supply 210, the one or more LEDs produce illuminationthat is captured and analyzed by a spectrum analyzer 212. For eachiteration, the resulting spectral characteristics associated with thedriving condition is saved in a lamps color space map 214 on a memory216.

In some embodiments, the test chamber 206 can include a thermal sensor218. In some embodiments, the temperature measured at the thermal sensor218 is also stored in the lamps color space map 214. In otherembodiments, the temperature measured at the thermal sensor 218associated with the driving condition is saved to a separate temperaturemap.

After the computer system 208 maps through a range of possible drivingconditions for each color channel or each LED of the tunable lightmodule 204, the computer system 208 can finalize the lamps color spacemap 214. The computer system 208 can receive performance metricconstraints 220 (e.g. from an agent of the manufacturer). The computersystem 208 can compute the color mixing plan 202 based on the lampscolor space map 214 and the constraints 220. The computer system 208 canselect optimal coefficients, flux values, and/or or driving conditionvalues corresponding to each color characteristic, such as the CCT, thatsatisfy the constraints 220, such as brightness, CRI, efficiency, orefficacy. The computer system 208 can associate the computed colormixing plan 202, the constraints 220 and the lamps color space map 214with a module identifier 222 of the tunable light module 204. In someembodiments, the computer system 208 then saves the color mixing plan202 onto a memory of the tunable light module 204 and uploads theconstraints 220 and the lamps color space map 214 to a cloud datastorage for future reference.

In some embodiments, the computer system 208 can also compute a thermalmodel 224 that corresponds to the tunable light module 204. The thermalmodel 224 can be generated based on the temperature map. The thermalmodel 224 can determine the transient junction temperature produced bydriving the LEDs of the tunable light module 204. The thermal model 224can also be saved onto a memory of the tunable light module 204 suchthat the tunable light module 204 can determine its junction temperaturein real-time after deployment. In some embodiments, the tunable lightmodule 204 can accurately produce illumination to a specific spectralcharacteristic based on the color mixing plan 202 and the junctiontemperature determined from the thermal model 224.

FIG. 2B is a flow chart illustrating a method 270 of generating a colormixing plan, such as the color mixing plan 202, at a pre-deploymentstage of a tunable light module (e.g., the tunable light module 204), inaccordance with various embodiments. The color mixing plan can enablethe tunable light module to produce adjustable CCTs so that it may beadjusted between, for example, different “white”/CCT levels. Further,during such adjustment the color tunable module can maintain, maximize,or optimize its CRI according to the color mixing plan.

At step 274, the model builder system 200 can index through a range ofdriving conditions to model a set of LEDs for the tunable light modulein the lamps color space map 214. This discussion will involve themodeling of LEDs, but in other embodiments, the tunable light module caninclude light sources/lamps other than LEDs. Modeling LEDs can alsoinclude gathering manufacturer data sheets that specify LED performancedata under specific conditions, and developing functional approximationsof LED performance by, for example, fitting to the performance datausing a least mean squares method. In this way, gaps in published LEDperformance data can be filled. Further, new relationships between LEDperformance variables can be developed. For example, a function for thecurrent required to generate a desired luminous flux from an LEDoperating at a given temperature can be developed by iterating throughthe range of driving conditions and monitoring the output illumination.

At step 276, constraints for the LEDs of the tunable light module areselected. Constraints can include, for example, constraints on theelectrical or physical properties of the tunable light module, such asthe total luminous flux, the total luminous efficacy, the total luminousefficiency, and the maximum operating temperature. Further, constraintscan include constraints on the color properties of the tunable lightmodule, such as constraints on the CCT, the CRI, the color difference(e.g., as defined in CIEDE 2000), the delta-UV (e.g., as defined in CIE1961), or the xy color coordinate.

At step 278, the model builder system 200 can generate a thermal modelfor the LEDs. At step 280, the model builder system 200 can compute acolor mixing plan for the set of LEDs of the tunable light module. Thecolor mixing plan can specify the luminous flux required from all LEDsin a lighting node to achieve a desired CCT, while maintaining oroptimizing a desirable CRI. The model builder system 200 can deploy abrute force algorithm to solve for the optimal flux. For example, themodel builder system 200 can select a total luminous flux of 1000lumens, and then by stepping through possible combinations of luminousflux for each LED in the tunable light module while maintaining thetotal luminous flux. Thus, for example, a first LED may be set to output990 lumens, a second LED may be set to output 5 lumens, and a third LEDmay be set to output 5 lumens, while the CCT and the CRI of the tunablelight module can be measured and/or computed. Continuing the brute forcealgorithm, the first LED may be set to output 985 lumens, the second LEDmay be set to output 10 lumens, and the third LED may be set to output 5lumens, and the CCT and the CRI of the tunable light module can bemeasured and/or computed again.

Notably, in this example a step size of 5 lumens has been used, but inother embodiments a different step size can be selected. Larger stepsizes can be used when results vary slowly. The brute force algorithmmay be made further manageable by avoiding combinations that drive thetotal light output away from the Planck locus. As is known in the art,the Planck locus (i.e. the Plankian locus) is a line or region in achromaticity diagram away from which a CCT measurement ceases to bemeaningful. Thus, for example, a combination which has too much redoutput, thereby driving the output of the entire lighting node away fromthe Plank locus, can be avoided.

Step 280 may include computing a performance evaluation for LEDs of thetunable light module. For example, the CRI, luminous efficacy, luminousefficiency, color difference, delta-UV, or other parameters can beevaluated against the CCT. For example, FIG. 2D is a graph illustratingcorresponding luminous efficacy of color points in the color mixing planof FIG. 2B. The luminous efficacy is illustrated as a dashed line 252.The dashed line 252 corresponds to a particular set of color pointsgenerated by mixing the luminous outputs of white, red, amber, and greenLEDs.

At step 282, the thermal model and the color mixing plan is stored in amemory of the tunable light module. The color mixing plan may be storedas, for example, a look-up table of points on the curves of luminousflux versus CCT, or as, for example, a functional approximation set ofcoefficients. The luminous flux can be directly correlated with thedriving conditions (e.g., driving current) of a LED. Notably, in oneembodiment the storage of a look-up table is memory intensive, and inanother embodiment the storage of coefficients is processor- orlogic-intensive. In the latter case, a processor or other controlcircuitry can be utilized to calculate polynomial results based onstored coefficients.

FIG. 2C is a graph illustrating an example portion of a color mixingplan, such as the color mixing plan 202, including an optimized CRI. Thecolor mixing plan depicts the luminous flux (in lumens) of a white LED,a red LED, an amber LED, and a green LED for various increasing CCTs (inKelvins). The increasing output of the white LED, and the decreasingoutputs of the red, amber, and green LEDs, with increasing CCT have beengenerated by the brute force algorithm to maximize the CRI, depicted indashed line 250. Notably, at a given CCT, other valid combinations ofwhite, red, amber, and green output exist, but the combination depictedin color mixing plan actually achieves the optimum CRI at the dashedline 250.

Values in color mixing plan can be calculated in several ways. Forexample, the CCT in color mixing plan can be calculated by additivecolor mixing with CIE chromaticity coordinates, wherein the CCT is theweighted average of the CIE chromaticity coordinates of each LED usingluminous flux as the weighting factor. Alternatively, the CCT can becalculated by spectral color mixing using spectral power distributionsof LEDs, wherein the combined spectral power distribution, from whichthe CCT can be computed, is the weighted average of the spectral powerdistributions of each LED using luminous flux as the weighting factor.

FIG. 3 is a block diagram of a LED-based lamp module 300 (e.g., thetunable light module 204 of FIG. 2A), in accordance with variousembodiments. The LED-based lamp module 300 includes a color model store302, a communication interface 304, a control circuitry 306, atemperature sensor 308, a point light source 310 comprising differentcolor LEDs 312, a mixing chamber 314, power circuitry 316 includingcurrent drivers 318 for the color LEDs 312, a power source 320, a lightsensor 322, or any combination thereof. The color model store 302 is amemory device or a portion of a memory device for storing a color mixingplan as defined above.

The communication interface 304 can include a hardware port for a wiredconnection or a radio antenna for establishing wireless communication.In some embodiments, the communication interface 304 can includemultiple radio antennas, such as one for transmitting and one forreceiving. The communication interface 304 can execute communicationprotocol instructions for formatting a signal (e.g. a digital or ananalog signal) to transmit through the hardware port or the radioantenna. Likewise, the communication interface 304 can execute thecommunication protocol instructions to interpret a signal (e.g., adigital or analog signal) received through the hardware port or theradio antenna. The communication protocol instructions, for example, canbe implemented by a processor configured with software executableinstructions. These executable instructions can be stored in a memorydevice, such as the same memory device as the color model store 302 oranother memory device. For another example, the instructions can beimplemented by application-specific integrated circuit, a programmablecontroller, field programmable gate array (FPGA), other digital oranalog circuitry, or any combination thereof.

The control circuitry 306 executes control instructions to operate theLED-based lamp module 300. The control circuitry 306 can execute lighttuning commands received through the communication interface 304. Forexample, the control circuitry 306 can determine adjustment commands tothe power circuitry 316 including the current drivers 318. The controlcircuitry 306 can also detect context of information within theLED-based lamp module 300. For example, the control circuitry 306 candetermine the context via measurements taken from the temperature sensor308, the light sensor 322, power measurement circuit (e.g., for voltageor current) in the power circuitry 316, or any combination thereof. Thecontrol circuitry 306 can generate and implement a schedule to reportcontext information and sensor measurements to the controller via thecommunication interface 304.

The control circuitry 306 can execute various other user-initiated,conditional (i.e., a background/passive command triggered when acontextual condition is detected), or scheduled commands (i.e., abackground/passive command executed sua sponte by the control circuitry306 in accordance with a schedule). Such commands can include acalibration command, a light maintenance or testing command, a lighteffect sequence command (i.e., executing a series of light/color tuningcommands in accordance with a preset sequence or schedule), anoptical/visual communication command (e.g., executing a light effectsequence and/or monitoring for a nearby light effect sequence for thepurpose of communication), or any combination thereof. Theoptical/visual communication command can be configured foroptical/visual communication between lamp modules (e.g., digitalcommunication), or between the LED-based lamp module 300 and a nearbyperson (e.g., human understandable communication).

The control circuitry 306 can communicate with a light controlapplication, in real time or asynchronously, running on a controllerconnected through the communication interface 304. In some embodiments,the control circuitry 306 can communicate with a light control service,in real time or asynchronously, provided by a computer server. Thecontrol circuitry 306 and the light control service can relay its backand forth communications through the controller.

In some embodiments, the communication interface 304 can receivecommands to reconfigure the communication protocol portion of thecommunication interface 304 (e.g., via reconfiguring the instructionsfor execution by the communication interface 304). In some embodiments,the communication interface 304 can receive commands to reconfigure orupdate the control logics of the control circuitry 306 (e.g., viareconfiguring the instructions for execution by the communicationinterface 304).

The control circuitry 306 can use the temperature sensor 308 to measureor approximate an operating temperature of the point light source 310.In order to provide accurate and consistent color characteristics, thecontrol circuitry 306 uses the color mixing plan in the color modelstore 302 to determine the proper operating conditions (e.g., drivingcurrents to the color LEDs 312) to achieve the target lightcharacteristics. The color mixing plan, for example, can map operatingtemperature and light characteristics to driving currents. Hence, thecontrol circuitry 306 can use the temperature sensor 308 to determinethe operating temperature at the point light source 310. In someembodiments, because the color LEDs 312 in the point light source 310are so small and closely packed that it is difficult to place thetemperature sensor 308 at the point light source 310, the temperaturesensor 308 is placed at a different location to approximate theoperating temperature. For example, the temperature sensor 308 can belocated at a heat sink of the point light source 310 or a temperaturepad. In some embodiments, prior to deployment of the LED-based lampmodule 300, a model builder computer system (i.e., a computer systemconfigured to model behaviors of the LED-based lamp module 300) thatbuilds the color mixing plan can also build a temperature variationmodel. The temperature variation model can map an observed temperatureat the temperature sensor 308 to the actual operating temperature of thecolor LEDs 312. In some embodiments, the temperature variation model canalso approximate the operating temperature based on driving currentsand/or running time of the color LEDs 312.

When executing a command to adjust a light characteristic of one of thecolor LEDs 312, the control circuitry 306 can implement a jitteravoidance mechanism when adjusting the driving current of the color LED.A visual “jitter” is an observable unsteady variance or noise when aperson is observing the LED-based lamp module 300 executing anadjustment of the light characteristic in discrete steps. The jitteravoidance mechanism computes discrete steps in adjusting the drivingcurrent such that the person is unable to observe the visual jitter. Forexample, this can be achieved by having finer discrete steps or creatingdiscrete steps in a pattern to emulate continuous adjustment.

The point light source 310 can comprise the different color LEDs 312.The color LEDs 312 enables the point light source 310 to produce a widerange of color temperature, brightness, hue, and saturation. Forexample, mixing the light produced by the color LEDs 312 can producenear-white light that emulates a blackbody radiator, such as the sun.The point light source 310 is advantageous because it enables sensors toprovide instant feedback from a single location for all the color LEDs312. For example, this is useful to use the light sensor 322 for are-calibration process. The light sensor 322 can be a PIN diode, atri-stimulus sensor (e.g., a colorimeter), or a spectrum analyzer.

The mixing chamber 314 is an optical component around the point lightsource 310 to manipulate the light produced from the point light source310. The mixing chamber 314 can collect the light. For example, themixing chamber 314 can have a portion to collect the light using a shellwith a reflective inner surface. The inner reflective surface can be areflective coating. Alternatively, the shell can be of a material with ahigh refractive index that causes total internal reflection at themajority of incident angles from the light collection portion of theshell or the color LEDs 312.

The shell can have at least a close end adjacent to and under the pointlight source 310 (e.g., where the point light source 310 sits on acircuit board, the close end can be under the circuit board). In someembodiments, the close end can have a reflective surface as well. Themixing chamber 314 can be narrowest around the close end and expands insize away from the point light source 310. For example, the shell can bea parabolic shape to collect the light. The parabolic shell can surroundthe point light source 310 to collect the omnidirectional light and pipeit at a direction away from the close end.

The mixing chamber 314 can have a portion to mix the light, includingpatterns on the shell to promote light rays from the different colorLEDs 312 to mix with each other. The portion to mix light can mix thelight without changing the directionality of the light rays that aremoving away from the point light source 310 (e.g., mixing the light on aplane perpendicular to the direction of the light rays from the pointlight source 310). The mixing chamber 314 can have a portion tocollimate or redirect the light outside of the shell. The mixing chamber314 can have an exit aperture in the shell to output the light from theshell. In some embodiments, the mixing chamber 314 can be supplementedwith a modular cover. The modular cover can be used to furthermanipulate the light, including acting as a diffuser, light directionchanger, or filter.

The power circuitry 316 includes the current drivers 318 for the colorLEDs 312. The power circuitry 316 draws power from the power source 320,which can be a battery or a DC power supply that converts AC power toDC. The current drivers 318 are coupled to the control circuitry 306.Each of the current drivers 318 can control at least one of the colorLEDs 312. The control circuitry 306 can command each of the currentdrivers 318 to drive its respective LED at a particular current level.

Portions of components (e.g., circuitry, storage, sensors, etc.)associated with the LED-based lamp module 300 may each be implemented inthe form of special-purpose circuitry, in the form of one or moreappropriately programmed programmable processors, a single board chip, afield programmable gate array, a network capable computing device, avirtual machine, a cloud-based terminal, or any combination thereof. Forexample, the components described can be implemented as instructions ona tangible storage memory capable of being executed by a processor orother integrated circuit chip. The tangible storage memory may bevolatile or non-volatile memory. In some embodiments, the volatilememory may be considered “non-transitory” in the sense that it is nottransitory signal. Memory space and storages described in the figurescan be implemented with the tangible storage memory as well, includingvolatile or non-volatile memory.

Each of the components may operate individually and independently ofother components. Some or all of the components may be executed on thesame host device or on separate devices. The separate devices can becoupled together through one or more communication channels (e.g.,wireless or wired channel) to coordinate their operations. Some or allof the components may be combined as one component. A single componentmay be divided into sub-components, each sub-component performingseparate method step or method steps of the single component.

In some embodiments, at least some of the components share access to amemory space. For example, one component may access data accessed by ortransformed by another component. The components may be considered“coupled” to one another if they share a physical connection or avirtual connection, directly or indirectly, allowing data accessed ormodified from one component to be accessed in another component. In someembodiments, at least some of the components can be upgraded or modifiedremotely (e.g., by reconfiguring executable instructions that implementsa portion of the components). The LED-based lamp module 300 may includeadditional, fewer, or different components for various applications.

FIG. 4 is an illustration of a configurable lamp system 400 to operate atunable light module, in accordance with various embodiments. Theconfigurable lamp system 400 includes one or more LED-based lamp modules(e.g., a lamp module 402A, a lamp module 402B, and a lamp module 402C,collectively as the “lamp modules 402”). The lamp modules 402 mayproduce directional light, linear light (e.g., light along a curved orstraight line), collimated light, spot light, multidirectional light,omnidirectional light (e.g., point light source), or other geometries.In some embodiments, the lamp modules 402 can be configured withdifferent modular covers (e.g., a light collector cover 404A or adiffuser cover 404B, collectively as the “lamp module covers 404”). Thelamp modules 402 can be independently replaceable. The configurable lampsystem 400 is able to produce a target light characteristic (e.g., CCT,hue, saturation, brightness, or any combination thereof) in response toreceiving a light tuning command utilizing a color mixing plan. The lampmodules 402 can each include an LED set. The LED set can include LEDs ofat least two colors.

The lamp modules 402 may be configured with one or more mechanisms forcommunicating with an external control device. For example, the lampmodules 402 can communicate with a wired controller 406A via an adapterbox 408. The wired controller 406A, for example, can be a DMX controlbox. The adapter box 408 is configured to convert communication signalbetween different communication protocols (e.g., DMX, Lutron, ZigbeeLight Link, digital addressable lighting interface (DALI), Bluetooth,Bluetooth LE, etc.). The adapter box 408 can be configured for wiredcommunication, wireless communication, or both. For example, the adapterbox 408 may connect with at least a subset of the lamp modules 402 via awired connection and communicate with the wired controller 406A via adifferent wired connection. In another example, the adapter box 408 mayconnect with at least a subset of the lamp modules 402 via a wirelessprotocol (e.g., Bluetooth LE) and communicate with the wired controller406A via a wired connection or a wireless controller 406B via a wirelessconnection (e.g., Bluetooth, Wi-Fi or Wi-Fi direct).

In some embodiments, one or more of the lamp modules 402 can alsocommunicate directly with a wireless controller 406B via a wirelessprotocol. These lamp modules can include an internal wireless module tocommunicate directly with the wireless controller 406B. Alternatively,these lamp modules can communicate wirelessly through the adapter box408. The adapter box 408 can be configured for digital to digitalcommunication (i.e., digital to/from the lamp modules 402 and digitalto/from the wireless controller 406B), digital to analog communication(i.e., digital to/from the lamp modules 402 and analog to/from thewireless controller 406B), analog-to-digital communication (i.e., analogto/from the lamp modules 402 and digital to/from the wireless controller406B), or analog to analog communication (i.e., analog to/from the lampmodules 402 and analog to/from the wireless controller 406B). In apreferred embodiment, the adapter box 408 is configured to communicatedigitally to the lamp modules 402 to provide precise numeric values oflight characteristics. In some embodiments, the adapter box 408 isconfigured to communicate with a 0 to 10V dimmer acting as the wiredcontroller 406A, and hence, takes in an analog signal that is thenconverted to a digital command to the lamp modules 402.

Further, the adapter box 408 can include one or more channels ofcommunication to each of the lamp modules 402. At least one of thechannels can provide color temperature control. At least one of thechannels can provide brightness control. At least one of the channelscan provide hue control. At least one of the channels can providesaturation control.

The adapter box 408 may be connected to the lamp modules 402 via theinterconnect 410. In some embodiments, the adapter box 408 can beconnected to multiple interconnects to relay commands to and data frommultiple groups of lamp modules. The interconnect 410 can seriallylinked together one or more of the lamp modules 402 such that a singleconnection of the interconnect 410 to the adapter box 408 enables thewired controller 406A or the wireless controller 406B to control everyone of the lamp modules 402 connected to the interconnect 410. Theinterconnect 410, for example, can be a RS485 bus.

In some embodiments, the adapter box 408 can draw power from a wiredconnection to the wired controller 406A, from a wired connection (e.g.,the interconnect 410) to one of the lamp modules 402, or both. In someembodiments, the adapter box 408 can have its own power source. In someembodiments, the adapter box 408 can draw power from a wired connectionto supplement power drawn from an internal power source or vice versa.

In some embodiments, the wired controller 406A or the wirelesscontroller 406B can be connected to a core network (e.g., the Internet),such as through a network equipment (e.g., a wireless WiFi router) or acellular Internet provider (e.g., LTE, 3G, etc.). A computer server 424in the core network can implement a light control service that isaccessible by the wired controller 406A or the wireless controller 406B.The wired controller 406A or the wireless controller 406B, for example,can implement a user interface for controlling the lamp modules 402. Oneor more of the functionalities of the wired controller 406A or thewireless controller 406B can be assisted by the light control service,including re-calibration, maintenance, storage of color mixing plans,storage of light adjustment history, storage of lamp module groups,storage of user preference of light settings, storage of conditionalrules associated with light settings (e.g., automatically sending lighttuning commands based on an observable context at one or more of thelamp modules 402), etc.

FIG. 5 is a flow chart of a method 500 of pre-computing adjustments to acolor mixing plan of a tunable light module (e.g., the LED-based lampmodule 300 of FIG. 3) at the pre-deployment stage to supportrecalibration after deployment, in accordance with various embodiments.At step 502, a model builder system, such as the model builder system200 of FIG. 2A, can generate a color mixing plan for the tunable lightmodule. For example, step 502 can be the method 270 of FIG. 2B.

At step 504, the model builder system can identify color points in acolor spectrum for pre-optimization against potential degradation. Atstep 506, the model builder system can select optimization constraints(e.g., including trade off amongst initial lumen, CRI threshold,efficiency threshold, efficacy threshold, or any combination thereof)for light produced from the tunable light module. At step 508, the modelbuilder system can estimate a level of color degradation of anindividual lamp (e.g., LED) or a color channel (e.g., lamps of the samecolor).

At step 510, the model builder system can compute alternativecoefficients for the color mixing plan at the identified color pointsfor the estimated level of color degradation based on the selectedoptimization constraints. At step 512, the model builder system canstore the alternative coefficients, associated with the color points andthe estimated degradation level, together with or in the color mixingplan in the tunable light module.

FIG. 6 is a flow chart of a method 600 of recalibrating a color mixingplan of a tunable light module (e.g., the LED-based lamp module 300 ofFIG. 3) after deployment, in accordance with various embodiments. Atstep 602, a control circuitry (e.g., the control circuitry 306 of FIG.3) of the tunable light module can designate a CCT level to operate. Atstep 604, the control circuitry can drive a lamp (e.g., an LED) in thetunable light module to produce a colored light. The control circuitrycan drive the lamp according to a color mixing plan, such as the colormixing plan produced at step 502 of FIG. 5, to achieve the designatedCCT level. In some embodiments, in order to measure a lightcharacteristic of the lamp, a single lamp is driven according to thecolor mixing plan for the CCT level, even when the color mixing plan forthe CCT level may indicate that, to achieve the CCT level, multiplelamps have to be used.

At step 606, the control circuitry can measure a light characteristic ofthe colored light using a light sensor in the tunable light module. Forexample, the control circuitry can measure the brightness of the lamp.At step 608, the control circuitry can detect a degradation by comparingthe measured light characteristic against an expected lightcharacteristic. A memory of the tunable light module may store theexpected light characteristic. For example, the memory can store theexpected brightness of the lamp at the designated CCT level.

At step 610, the control circuitry can adjust a current level fordriving the lamp at the designated CCT level by referencing the colormixing plan and an alternative coefficient for the detected degradation.The memory of the tunable light module may store both the color mixingplan and the alternative coefficient. For example, the alternativecoefficient can be the alternative coefficient computed at step 510 ofFIG. 5.

Where there is no corresponding alternative coefficient for the detecteddegradation, the control circuitry can interpolate between alternativecoefficients at step 612. For example, the control circuitry candetermine the closest degradation levels represented by alternativecoefficients are stored in or associated with the color mixing plan. Thecontrol circuitry can then compute a substitute coefficient byinterpolating (e.g., linearly interpolate) between the alternativecoefficients corresponding to these closest degradation levels.

FIG. 7 is a flow chart of a method 700 of real-time re-optimization of acolor mixing plan of a tunable light module (e.g., the LED-based lampmodule 300 of FIG. 3) after deployment, in accordance with variousembodiments. At step 702, a control circuitry (e.g., the controlcircuitry 306 of FIG. 3) of the tunable light module can provide adriving current to a lamp of the tunable light module to produce lightat a designated CCT according to a color mixing plan.

At step 704, the control circuitry can monitor spectral profile of thelight produced from the lamp using a light sensor in the tunable lightmodule. For example, the light sensor can be a tristimulus sensor or aspectral analyzer. The tristimulus sensor measures filtered light usingat least three sensors adapted to have the same sensitivity as humaneyes and thus directly measures the tristimulus values X, Y, and Z. Thespectral analyzer can include multiple sensors that measure the spectralprofile of the light at respective wavelengths or respective narrowwavelength ranges.

At step 706, the control circuitry can determine a degradation of thelight produced from the lamp for the designated CCT. For example, thecontrol circuitry can compare the spectral profile measured at step 704with an expected spectral profile of the lamp stored in a memory of thetunable light module.

At step 708, the control circuitry can send the spectral profile to anexternal device (e.g., the wireless controller 406B of FIG. 4) to bedelivered to a cloud server (e.g., the computer server 424 of FIG. 4)associated with the color mixing plan. The cloud server can store alamps color space map (e.g., the lamps color space map 214 of FIG. 2A).In some embodiments, based on the spectral profile received at the cloudserver, the cloud server can update the lamps color space map at step710. Whether to execute step 710 can depend on the quality of the lightsensor used at step 704. In most cases, the light sensor used is not ofa high enough quality to warrant an update to the lamps color space mapthat was built using powerful spectrum analyzer(s).

The cloud server can update the color mixing plan based on the spectralprofile of the degradation at step 712. For example, the cloud servercan use the updated lamps color space map. For another example, thecloud server can use the spectral profile to identify a tristimulusshift in the lamps color space map and realign the lamps color spacemap. Once the lamps color space map is updated or realigned, the colormixing plan can be updated using the (updated or realigned) lamps colorspace map.

When updating the color mixing plan, the cloud server can utilize thesame set of constraints (e.g., on performance metrics) used to computethe original color mixing plan. Alternatively, the cloud server canreceive a new set of constraints and update the color mixing plan usingthe new set of constraints. In some embodiments, where the originalconstraints cannot be met, the cloud server can determine a new set ofconstraints based on a ranking of priority of the performance metrics.At step 714, the tunable light module can receive the updated colormixing plan back from the cloud server.

While processes or blocks are presented in a given order, alternativeembodiments may perform routines having steps, or employ systems havingblocks, in a different order, and some processes or blocks may bedeleted, moved, added, subdivided, combined, and/or modified to providealternative or subcombinations. Each of these processes or blocks may beimplemented in a variety of different ways. Also, while processes orblocks are at times shown as being performed in series, these processesor blocks may instead be performed in parallel, or may be performed atdifferent times.

FIG. 8 is a block diagram of an example of a computing device 800, whichmay represent one or more computing device or server described herein,in accordance with various embodiments. The computing device 800 canrepresent the wired controller 406A, the wireless controller 406B or thecomputer server 424 of FIG. 4. The computing device 800 includes one ormore processors 810 and memory 820 coupled to an interconnect 830. Theinterconnect 830 is an abstraction that represents any one or moreseparate physical buses, point-to-point connections, or both connectedby appropriate bridges, adapters, or controllers. The interconnect 830,therefore, may include, for example, a system bus, a PeripheralComponent Interconnect (PCI) bus or PCI-Express bus, a HyperTransport orindustry standard architecture (ISA) bus, a small computer systeminterface (SCSI) bus, a universal serial bus (USB), IIC (I2C) bus, or anInstitute of Electrical and Electronics Engineers (IEEE) standard 1394bus, also called “Firewire”.

The processor(s) 810 is/are the central processing unit (CPU) of thecomputing device 800 and thus controls the overall operation of thecomputing device 800. In certain embodiments, the processor(s) 810accomplishes this by executing software or firmware stored in memory820. The processor(s) 810 may be, or may include, one or moreprogrammable general-purpose or special-purpose microprocessors, digitalsignal processors (DSPs), programmable controllers, application specificintegrated circuits (ASICs), programmable logic devices (PLDs), trustedplatform modules (TPMs), or the like, or a combination of such devices.

The memory 820 is or includes the main memory of the computing device800. The memory 820 represents any form of random access memory (RAM),read-only memory (ROM), flash memory, or the like, or a combination ofsuch devices. In use, the memory 820 may contain a code 870 containinginstructions according to the mesh connection system disclosed herein.

Also connected to the processor(s) 810 through the interconnect 830 area network adapter 840 and a storage adapter 850. The network adapter 840provides the computing device 800 with the ability to communicate withremote devices, over a network and may be, for example, an Ethernetadapter or Fibre Channel adapter. The network adapter 840 may alsoprovide the computing device 800 with the ability to communicate withother computers. The storage adapter 850 allows the computing device 800to access a persistent storage, and may be, for example, a Fibre Channeladapter or SCSI adapter.

The code 870 stored in memory 820 may be implemented as software and/orfirmware to program the processor(s) 810 to carry out actions describedabove. In certain embodiments, such software or firmware may beinitially provided to the computing device 800 by downloading it from aremote system through the computing device 800 (e.g., via networkadapter 840).

The techniques introduced herein can be implemented by, for example,programmable circuitry (e.g., one or more microprocessors) programmedwith software and/or firmware, or entirely in special-purpose hardwiredcircuitry, or in a combination of such forms. Special-purpose hardwiredcircuitry may be in the form of, for example, one or moreapplication-specific integrated circuits (ASICs), programmable logicdevices (PLDs), field-programmable gate arrays (FPGAs), etc.

Software or firmware for use in implementing the techniques introducedhere may be stored on a machine-readable storage medium and may beexecuted by one or more general-purpose or special-purpose programmablemicroprocessors. A “machine-readable storage medium”, as the term isused herein, includes any mechanism that can store information in a formaccessible by a machine (a machine may be, for example, a computer,network device, cellular phone, personal digital assistant (PDA),manufacturing tool, any device with one or more processors, etc.). Forexample, a machine-accessible storage medium includesrecordable/non-recordable media (e.g., read-only memory (ROM); randomaccess memory (RAM); magnetic disk storage media; optical storage media;flash memory devices; etc.), etc.

The term “logic”, as used herein, can include, for example, programmablecircuitry programmed with specific software and/or firmware,special-purpose hardwired circuitry, or a combination thereof.

Some embodiments of the disclosure have other aspects, elements,features, and steps in addition to or in place of what is describedabove. These potential additions and replacements are describedthroughout the rest of the specification. In some embodiments, anLED-based lamp drives an LEDs array to flash color sets of the LEDsarray in succession. The LED-based lamp can then measure colorintensities for each of the color sets with an optical sensor in thelight source. A logic unit (e.g., a processor or a controller) of theLED-based lamp can calculate a color ratio between two of the colorintensities including a baseline color intensity of a baseline colorset. By comparing the color ratio with a factory recalibration settingratio stored on a memory, the logic unit can adjust a driving current tothe baseline color set of the LEDs array to return the color ratio tothe factory recalibration setting ratio.

What is claimed is:
 1. A computer-implemented method of operating amodel builder system for enabling recalibration of a tunable lightsystem, comprising: generating a color mixing plan for a tunable lightmodule having multiple lamps of at least two colors, wherein the colormixing plan includes coefficients used to determine how to drive each ofthe lamps to produce an output illumination of the tunable light module,the coefficients associated with the output illumination having aparticular color characteristic; selecting a constraint of a performancemetric of illumination produced from the tunable light module;estimating a degradation level of a lamp in the tunable light module;computing alternative coefficients for the color mixing plan for theestimated degradation level based on at least the constraint; andstoring the alternative coefficients, associated with the estimateddegradation level, in the tunable light module.
 2. The method of claim1, wherein storing the alternative coefficients occurs prior todeployment of the tunable light module such that the tunable lightmodule is capable of being recalibrated after deployment.
 3. The methodof claim 1, wherein said estimating includes estimating degradationlevels of each of the lamps in the tunable light module; wherein saidcomputing includes computing sets of alternative coefficients for thecolor mixing plan, each of the sets corresponding to one of theestimated degradation levels based on at least the constraint; andwherein said storing includes storing the sets of alternativecoefficients in the tunable light module.
 4. The method of claim 1,wherein the color mixing plan is a lookup table that maps correlatedcolor temperature to driving current levels or output flux requirementsfor each of the lamps; and wherein the driving current levels or theoutput flux requirements are represented by the coefficients.
 5. Themethod of claim 1, wherein the color mixing plan is a polynomialfunction that takes a correlated color temperature as an input andprovides driving current levels or output flux requirements for each ofthe lamps; and wherein the coefficients are coefficients of thepolynomial function.
 6. The method of claim 1, wherein the constraint ofthe performance metric is a threshold of a maximum brightness,illumination efficiency, illumination efficacy, or a color renderingindex.
 7. The method of claim 1, further comprising: identifying colorpoints in a color spectrum; and wherein computing the alternativecoefficients includes computing the alternative coefficients forachieving illumination at the identified color points.
 8. The method ofclaim 1, wherein generating the color mixing plan comprises: indexingthrough a range of driving conditions to model a set of LEDs for thetunable light module in a lamps color space map; and selectingconstraints of performance metrics for the illumination produced by thetunable light module; and computing the color mixing plan for the lampsthat satisfies the constraints based on the lamps color space map. 9.The method of claim 8, wherein generating the color mixing plan furthercomprises generating a thermal model for the lamps in the tunable lightmodule.
 10. A method of operating a computer server comprising:receiving a spectral profile of a lamp having degraded in a tunablelight module that has multiple lamps of at least two colors; re-aligninglamps color space map that has test data of the lamp prior to deploymentof the tunable light module with the spectral profile; updating a colormixing plan associated with the tunable light module based on there-aligned lamps color space map by re-optimizing the color mixing planagainst a set of performance metric constraints on illumination producedby the lamps of the tunable light module; and sending the updated colormixing plan destined for the tunable light module.
 11. The method ofclaim 10, wherein sending the updated color mixing plan includes sendingthe updated color mixing plan to a mobile device associated with thetunable light module, wherein the mobile device is capable of routingthe updated color mixing plan to the tunable light module.
 12. Themethod of claim 10, wherein the color mixing plan prior to said updatingis stored in the computer server.
 13. The method of claim 10, whereinthe color mixing plan prior to said updating is received together withthe spectral profile.